To investigate the influence of potato cultivar on the functional and physicochemical properties of proteins from starch processing wastewater.

This research utilized yellow-fleshed potato and purple-fleshed potato as raw materials. Proteins were derived from the starch processing wastewater using the alkali-soluble acid precipitation method, and their functional and physicochemical properties were determined and compared.

The results demonstrated that the solubility, foaming capacity, water holding capacity and emulsifying stability of the proteins from purple-fleshed potato starch wastewater (PP) (42.03%, 59%, 5.53 g/g, 15.77 min)were significantly higher than those of yellow-fleshed potatoes (YP) (35.58%, 24%, 3.74 g/g, 12.28 min) (P<0.01). The emulsifying activity of YP reached 14.71 m²/g, significantly higher than that of PP (8.65 m²/g) (P<0.01). There was no significant difference in oil retention between PP and YP, which were 8.20 g/g and 8.42 g/g respectively (P>0.05). The average particle size of PP (511.66 nm±33.23 nm) was significantly smaller than that of YP (723.00 nm±39.84 nm)(P<0.05). The absolute value of the zeta potential of PP was 12.60 mV±1.22 mV, higher than that of YP(10.16 mV±0.21 mV). Amino acid composition analysis revealed that PP and YP exhibited similar amino acid profiles.Nevertheless, YP possessed significantly higher content of essential amino acids, nonessential amino acids and hydrophobic amino acids (83.323, 115.707 and 80.895 mg/g) compared with PP (70.954, 98.739 and 67.987 mg/g)(P<0.05 or P<0.01).

There are significant differences in the physicochemical, functional and nutritional properties between PP and YP, laying a data foundation for targeted resource utilization of wastewater proteins from various potato cultivars.